A hot runner system for an injection molding machine includes a hot runner manifold with a sprue bushing for the melt, nozzles connected to the hot runner manifold for insertion into the injection molding tool and, in the case of needle valve nozzles, drives for the adjustment of the valve needles in their longitudinal direction.
The drive for the adjustment of the needle is mounted on the hot runner manifold. The drive may be, for example, an hydraulic, a pneumatic, an electric or a magnetic drive. It is important that the drive and/or its housing be protected against the heat emanating from the hot runner manifold.
For this purpose, an arrangement in which a cooling device is installed in the lower part of the drive housing facing the manifold is already known from the prior art. This arrangement has the disadvantage that when the drive is changed the connections for the coolant flowing through the cooling device must also be disconnected. This not only requires additional time, but also causes the leakage of a limited amount of coolant.